Every year electronic devices become faster. This happens because of Moore's law which states that transistors, which are the major element of all electronic circuits, become smaller every year. This trend results in a higher density of the number of transistors that can be fabricated on a microchip. One of the biggest technological concerns of the 21st century is the possible saturation of Moore's law and as a consequence the improvement of device speed with time may come to an end.
Many techniques have been suggested to keep Moore's law relevant. One of them is the incorporation of photonic devices on Silicon (Si) microchips, which would further improve the speed of the next generation devices such as microchips and integrated circuits, with light being much faster than electricity.
Currently, the main high-volume industrial manufacturing technology that is used to produce integrated circuits, such as electronic microchips and computer microprocessors, is Complementary Metal-Oxide-Semiconductor (CMOS) technology. Current CMOS microchips in the microelectronics industry are based on (001) Silicon (Si) substrates. Hence initial photonic devices also have to be compatible with (001) Silicon. Unfortunately, Si itself cannot emit light. To circumnavigate this problem, in conventional systems, lasers made of other materials have been fabricated separately and then placed on the Si substrate.